The present invention relates to novel azoxy dyes of the general formula I in the form of the free acid 
where
n is 0 or 1, each
R1 is selected from the group consisting of methoxy, hydroxyl and carboxyl, each
R2 is selected from the group consisting of carboxyl, amino, C1-C4-alkylamino, allylamino, benzylamino and methoxycarbonylmethylamino, and the phenyl rings A may additionally be substituted by C1-C8-alkyl, unsubstituted or methyl- or halogen-substituted phenyl, hydroxyl, amino, nitro, halogen, carboxyl, N-benzylcarbamoyl, unsubstituted or nitro-, halogen-, C1-C4-alkoxy- or acetoxy-substituted phenylcarbamoyl and naphthylcarbamoyl or be benzofused,
their copper complexes, a process for preparing the copper complex dyes, azoxy dyes of the formula I in their partially or completely deacylated form, their copper complexes, colorants comprising these azoxy dyes and/or their copper complexes and their use for dyeing and printing natural or synthetic substrates.
CH-A-193 343, CH-A-196 252, CH-A-196 259, CH-A-196 260, CH-A-196 264, DE-A-26 51 369, EP-A-648 814 and EP-A-43 792 describe azoxy dyes containing various hydroxyaminonaphthalenesulfonic acids and their copper complexes.
DE-A-28 44 597 teaches a process for preparing copper-containing azoxy dyes whose coupling component is a 4-hydroxy-6-sulfophenylaminonaphthalene-2-sulfonic acid.
The prior art dyes are dull and frequently provide unlevel dyeings.
It is an object of the present invention to provide dyes which do not have the abovementioned disadvantages and which possess good application properties.
We have found that this object is achieved by the above-described dyes and their copper complexes.
Any alkyl appearing in the abovementioned formula may be straight-chain or branched.
Additionally substituted phenyl rings A may each bear 1, 2, 3 or 4, preferably 1 or 2, substituents, which may be different.
Halogen is fluorine, chlorine, bromine or iodine.
R2 is for example methylamino, ethylamino, propylamino, isopropylamino, butylamino, isobutylamino, sec-butylamino and tert-butylamino.
Substituents for the phenyl rings A include for example methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-, 3- or 4-bromophenyl, 2-, 3- or 4-methylphenyl, 2-, 3- or 4-nitrophenylcarbamoyl, 2-, 3- or 4-methoxyphenylcarbamoyl, 2-methoxy-4-nitro- and 2-methoxy-5-nitrophenylcarbamoyl, 2-, 3- or 4-ethoxyphenylcarbamoyl and 2-, 3- or 4-acetoxyphenylcarbamoyl.
In the description part and in the claims, the dyes of the formulae I, VI, VII, VIII and IX are depicted in the form of the free acids, but preferably they are present as salts, especially as alkali metal salts, and are isolated as salts from the synthesis. The formula depiction as free acid must therefore, as customary in the dye literature, be considered equivalent to the depiction as salt.
Suitable cations are derived from metal or ammonium ions. Metal ions are in particular the lithium, sodium or potassium ions. Ammonium ions for the purposes of the present invention are unsubstituted or substituted ammonium cations. Substituted ammonium cations include for example monoalkyl-, dialkyl-, trialkyl-, tetraalkyl- or benzyltrialkyl-ammonium cations for example diethanolammonium or cations derived from nitrogenous five- or six-membered saturated heterocycles, such as pyrrolidinium, piperidinium, morpholinium, piperazinium or N-alkylpiperazinium cations or their N-monoalkyl- or N,N-dialkyl-substituted products. Alkyl is here to be understood as meaning in general straight-chain or branched C1-C20-alkyl, which may be substituted by 1 or 2 hydroxyl groups and/or interrupted by from 1 to 4 oxygen atoms in ether function.
The dyes may be prepared by reacting an aminohydroxynaphthalenesulfonic acid of the formula II 
where n is 0 or 1, with an anhydride of the formula III 
where B is a single bond or imino, C1-C4-alkylimino or phenylimino and A is as defined above, in a weakly alkaline medium to form a coupling component of the formula IV 
This coupling component may be coupled with nitroanilines of the formula V 
where R1 is as defined above, as diazo component in a conventional manner before two resultant nitromonoazo dyes are reductively linked via an azoxy bridge to form the dyes of the invention.
The reducing agents used are preferably reducing sugars, for example D-glucose, in aqueous alkaline solution. The solution may be rendered alkaline for example by means of an alkali metal hydroxide such as sodium hydroxide or lithium hydroxide. Such reductions are common knowledge and described for example in EP-A-43 792. In addition, a reduction with customary reducing agents such as aldehydes e.g. formaldehyde or hydrazine hydrate is possible.
Suitable aminohydroxynaphthalenesulfonic acids II include for example 1-amino-8-hydroxynaphthalene-4,6-disulfonic acid, 2-amino-8-hydroxynaphthalene-6-sulfonic acid, 3-amino-8-hydroxynaphthalene-6-sulfonic acid, 4-amino-8-hydroxynaphthalene-6-sulfonic acid and particularly preferably 1-amino-8-hydroxynaphthalene-3,6-disulfonic acid.
Examples of anhydrides III are
phthalic anhydrides such as phthalic anhydride, 3-methyl-, 4-methyl-, 3,6-dimethyl-, 4-tert-butyl-, 3,4,5,6-tetramethyl-, 3-o-tolyl-, 3,6-diphenyl-, 3-hydroxy-, 4-carboxy-, 3-amino-, 3-nitro-, 4-nitro-4-(2,4-dichlorophenyl)carbamoyl-, 4-(3,4-dichlorophenyl)carbamoyl-, 4-(2-methoxy-5-chlorophenyl)carbamoyl-, 4-(3-nitrophenyl)carbamoyl-, 4-(2-methoxy-4-nitrophenyl)carbamoyl-, 4-(2-methoxy-5-nitrophenyl)carbamoyl, 4-(4-acetamidophenyl)carbamoyl-, 4-(2-ethoxyphenyl)carbamoyl-, 4-naphthylcarbamoyl-, 4-benzylcarbamoyl-, 3-fluoro-, 4-fluoro-, 3,4,5,6-tetrafluoro-, 3,6-difluoro-, 3,4-difluoro-, 3-chloro-, 4-chloro-, 3,6-dichloro-, 4,5-dichloro-, 3,4,5,6-tetrachloro-, 4-bromo-, 3,4,5,6-tetrabromo-, 3,4,5,6-tetraiodo- and 3-(4-bromo)phenyl-phthalic anhydride,
isatoic anhydrides such as isatoic anhydride, 6-methyl-, 6-hydroxy-, 5-hydroxy-, 4-carboxy-, 4-nitro-, 5-nitro-, 5-amino-, 6-fluoro-, 5-chloro-, 6-chloro-, 3,5-dichloro-, 5-bromo-, N-methyl-, N-ethyl-, N-benzyl-, N-allyl-, N-methyl-5-nitro-, N-methyl-5-chloro-, N-methyl-6-chloro- and N-methoxycarbamoylmethyl-isatoic anhydride, and also
naphthalene-1,2-dicarboxylic and naphthalene-2,3-dicarboxylic anhydrides.
The present invention further provides copper complex dyes and their mixtures which are obtainable by reacting dyes I with at least 0.1 mol equivalent of a copper donor. Preferably, 0.1-2 mol of a copper donor is used per mole of dye. Amounts above 2 mol equivalents are possible, but have no influence on the product. Incomplete formation of 2:1 complexes, i.e., the use of  less than 2 mol equivalents of the copper donors, provides mixtures of the uncomplexed, singly copper-complexed and doubly copper-complexed dyes.
The copper complex dyes conform to the general formula VI in the form of the free acid 
where at least one of M1 and M2 is copper(II) and any which is not is hydrogen and methyl, and n, R2 and A are each as defined above. When M1 or M2 is hydrogen and methyl, the methyl radical will form the methoxy group on the phenyl ring and the hydrogen will form the hydroxyl group on the naphthalene structure.
Copper complex dyes obtained by reaction with 0.5-1.7 mol, especially 0.5-1.5 mol, of copper donor per mole of dye are preferred.
The copper donors used may be salts which contain the copper as cation, for example copper sulfate, copper chloride or copper acetate. In some cases, the use of complex copper compounds is of advantage, for example in the form of copper-ammine complexes, such as coppertetrammine sulfates from copper sulfate and ammonia, pyridine or monoethanolamine, or in the form of compounds which contain the copper in complexed form, for example complex copper compounds of the alkali metal salts of aliphatic aminocarboxylic acids or hydroxycarboxylic acids, as of glycocoll, of lactic acid and in particular of tartaric acid, such as sodium copper tartrate.
The treatment with the copper donor takes place in an aqueous or organic/aqueous medium, for example at room temperature, if readily metallizable starting compounds are present, or by heating to 50-120xc2x0 C. in an open vessel, for example under reflux, or if necessary in a closed vessel under superatmospheric pressure, the pH conditions being determined by the nature of the metallization method chosen.
If desired, solvents, for example alcohol, dimethylformamide, etc., can also be added during the metallization.
Preference is given to dyes of the general formula VII in the form of the free acid 
where R1, R2 and A are each as defined above, and their copper complexes.
Preference is further given to dyes I where each R1 is methoxy and to the copper complexes obtainable therefrom.
Preference is also given to dyes I and their copper complexes where the phenyl rings A are unsubstituted, i.e., bear the R2 only, or C1-C4-alkyl-substituted.
Preference is given to the dyes I and VII and their copper complexes where each R2 is carboxyl. Preference is given in particular to dyes I and VII where R1 is methoxy, R2 is carboxyl and the phenyl rings A bear C1-C4-alkyl as further substituents or preferably are unsubstituted. The copper complexes obtainable therefrom are preferred in particular.
Preference is given in particular to the copper complex mixture of the preferred dyes which are obtained by reaction with 0.1-2, especially 0.5-1.7, mol equivalents of a copper donor.
The present invention further provides azoxy dyes of the general formula VIII in the form of the free acid 
where X is hydrogen or a radical of the formula 
and R1, R2 and A are each as defined above.
The present invention further provides copper complex dyes of the general formula IX in the form of the free acid 
where M1, M2 and X are each as defined above.
Preference is given to azoxy dyes of formula VIII in the form of the free acid where X is hydrogen.
Preference is further given to copper complex dyes of formula IX in the form of the free acid where X is hydrogen.
The azoxy dyes of the formula VIII are obtained as described above for the azoxy dyes of the formula I. The partial or complete detachment of the radical 
(deacylation) can be effected by controlling the pH after the reduction of the nitromonoazo dyes to the azoxy compound. Working in aqueous solution at a pH below 9 practically provides for complete deacylation to the azoxy dyes of the formula VIII (X=hydrogen).
The dye of the formula X 
is formally known from EP-A-648 814, where it is described in Example 3. However, it has been determined that, when this example is repeated, the monoazo dye of the formula XI 
is obtained instead of the abovementioned dye X.
The metal complex dyes of the invention can be used alone, in mixtures with each or one another and with the azoxy dyes I and III and together with other cationic or anionic compounds in the form of their solutions or in the form of powders or granules.
Dye preparations comprising the novel dyes of the formula I, VII, III and/or IX preferably further comprise polymers, such as polyvinylamines, polyvinylamides, polyvinyl acetates, polyvinyl alcohols, polyvinylpyrrolidones or copolymers of the respective monomers. Similarly, oligomers of ethyleneimine, ethylene oxide or propylene oxide or derivatives thereof may be used. Further preferred additives are glycols such as 1,2-glycol, 1,2-propanediol, 2,3-butylene glycol, diethylene glycol, triethylene glycol, ethyltetraglycol, dipropylene glycol, ethylene glycol monopropyl ether, methyldiglycol, triethylene glycol monobutyl ether, triethylene glycol monopropyl ether, diethylene glycol monoethyl ether, diethylene glycol dibutyl ether and particularly preferably urea.
They are very useful for dyeing or printing polymeric material, especially papery materials such as paper and paperboard, but also cellulose, cotton, leather, bast fibers, hemp, flax, sisal, jute, coir, straw or anionically modified fibers and also in recording fluids such as inks especially for ink-jet or printing inks.
The dyes of the invention are particularly useful in the production of pulp-dyed, sized and unsized paper. They are likewise useful for dyeing paper by the pulp method.
Paper, leather and cellulose are dyed in a conventional manner.
The copper complex dyes of the invention provide different bright blues. They have very good affinity for paper. The novel dyes and their preparations color the papermaking wastewater only minimally, if at all, which is particularly favorable from the aspect of keeping the water courses clean. They are substantive, do not marble on paper and are substantially pH-insensitive. Dyeings on paper are notable for good lightfastness. On prolonged exposure to light the hue changes on-tone.
The dyed papers, which exhibit good bleachability, are wetfast, not only with regard to water, but also with regard to milk, soapy water, sodium chloride solutions, fruit juices or sweetened mineral water, and are also stable to alcoholic drinks because of their good alcoholfastness.
The novel dyes can also be used for dyeing, padding or printing polyacrylonitrile textiles or anionically modified polyamide or polyester textiles.